The present invention relates to gas probes and more particularly to gas probes for sampling gases and vapors evolved from, or closely adjacent to, surfaces.
In order to sample gases evolved from, or closely adjacent to, potentially contaminated surfaces, detectors have been used which included a gas probe consisting essentially of an inverted funnel placed over the surface and a vacuum pump to draw air from around a perimeter of the funnel and into a detector. A cannister of activated charcoal was occasionally employed to purify the ambient air before permitting it to be drawn over the surface to remove interfering components from the gas.
The above method was limited in its sensitivity due to the effect of air temperature, humidity and environmental trace elements in the air. The presence of such elements changed the sensitivity of the detector and contributed errors to the measurement.